This is an amazing download manager, which is an add-on of Firefox. Not saying it's the best, however, if you are using Linux and looking for a good download manager, DownThemAll owns !!!
Homepage: http://downthemall.net/
Download: https://addons.mozilla.org/en-US/firefox/addon/201
I gave it a try and now it becomes my favorite one.
It supports downloads from almost all common network protocols, can resume downloads (also depending on the servers' allowance), just one click and download, especially, it can be used to download from various hosting sites like: rapidshare.com, megaupload.com, ....
Compare to others, I think I love DTA the most !